... I reckon if you were willing to do that ... and perhaps dance around the FV, chanting "Fly, Fly my pretties!!", as you pitched the yeast ... of course, in practice you wouldn't need to actually do this, you'd just need to (both, independently) be willing to tell the representative from the Revenue that this was what you did, should they ever ask ... then as far as the HMRC are concerned you'd probably be considered as co-habiting, let alone co-brewers, and any purpose that would fall under your friend's "own domestic use" would also come under your "own domestic use"
Cheers, PhilB
Video evidence or it never happened
